The Wnt gene family encodes a large class of secreted proteins related to the Int1/Wnt1 proto-oncogene and Drosophila wingless (“Wg”), a Drosophila Wnt1 homologue. (Cadigan et al. (1997) Genes & Development 11:3286-3305). Wnts are expressed in a variety of tissues and organs and play a major role in many developmental processes, including segmentation in Drosophila; endoderm development in C. elegans; and establishment of limb polarity, neural crest differentiation, kidney morphogenesis, sex determination, and brain development in mammals. (Parr, et al. (1994) Curr. Opinion Genetics & Devel. 4:523-528). The Wnt pathway is a master regulator in animal development, both during embryogenesis and in the mature organism. (Eastman, et al. (1999) Curr Opin Cell Biol 11: 233-240; Peifer, et al. (2000) Science 287: 1606-1609).
Wnt signals are transduced by the Frizzled (“Fz”) family of seven transmembrane domain receptors. (Bhanot et al. (1996) Nature 382:225-230). Wnt ligands bind to Fzd, and in so doing, activate the cytoplasmic protein Dishevelled (Dvl-1, 2 and 3 in humans and mice) (Boutros, et al. (1999) Mech Dev 83: 27-37) and phosphorylate LRP5/6. A signal is thereby generated which prevents the phosphorylation and degradation of Armadillo/β(beta)-catenin, in turn leading to the stabilization of β-catenin (Perrimon (1994) Cell 76:781-784). This stabilization is occasioned by Dvl's association with axin (Zeng et al. (1997) Cell 90:181-192), a scaffolding protein that brings various proteins together, including GSK3, APC, CK1, and β-catenin, to form the β-catenin destruction complex.
The Wingless-type (Wnt) Frizzled protein receptor pathway involves important regulatory genes that carry polymorphisms associated with primary carcinomas. In the course of downstream signaling, cytosolic β-catenin accumulates, translocates into the nucleus, and then enhances gene expression by complexing with other transcription factors. (Uthoff et al., Mol Carcinog, 31:56-62 (2001)). In the absence of Wnt signals, free cytosolic β-catenin is incorporated into a complex consisting of Axin, the adenomatous polyposis coli (APC) gene product, and glycogen synthase kinase (GSK)-3β. Conjunctional phosphorylation of Axin, APC, and β-catenin by GSK-3β designates β-catenin for the ubiquitin pathway and degradation by proteasomes. (Uthoff et al., Mol Carcinog, 31:56-62 (2001); Matsuzawa et al., Mol Cell, 7:915-926 (2001)).
Wnt/β-catenin signaling promotes cell survival in various cell types. (Orford et al., J Cell Biol, 146:855-868 (1999); Cox et al., Genetics, 155:1725-1740 (2000); Reya et al., Immunity, 13:15-24 (2000); Satoh et al., Nat Genet, 24:245-250 (2000); Shin et al., Journal of Biological Chemistry, 274:2780-2785 (1999); Chen et al., J Cell Biol, 152:87-96 (2001); Ioannidis et al., Nat Immunol, 2:691-697 (2001)). Wnt signaling pathway is also thought to be associated with tumor development and/or progression. (Polakis et al., Genes Dev, 14:1837-1851 (2000); Cox et al., Genetics, 155:1725-1740 (2000); Bienz et al., Cell, 103:311-320 (2000); You et al., J Cell Biol, 157:429-440 (2002)). Aberrant activation of the Wnt signaling pathway is associated with a variety of human cancers, correlating with the over-expression or amplification of c-Myc. (Polakis et al., Genes Dev, 14:1837-1851 (2000); Bienz et al., Cell, 103:311-320 (2000); Brown et al., Breast Cancer Res, 3:351-355 (2001); He et al., Science, 281:1509-1512 (1998); Miller et al., Oncogene, 18:7860-7872 (1999)). In addition, c-Myc was identified as one of the transcriptional targets of the β-catenin/Tcf in colorectal cancer cells. (He et al., Science, 281:1509-1512 (1998); de La Coste et al., Proc Natl Acad Sci USA, 95:8847-8851 (1998); Miller et al., Oncogene, 18:7860-7872 (1999); You et al., J Cell Biol, 157:429-440 (2002)).
International Application Number PCT/US2010/025813 describes N-(hetero)aryl, 2-(hetero)aryl-substituted acetamides for use as Wnt signaling modulators.
A need exists for agents and methods that modulate the Wnt signaling pathway, for example, agents having functional activity as Wnt inhibitors, thereby treating, diagnosing, preventing, and/or ameliorating Wnt signaling-related disorders. Furthermore, the ideal drug candidate should exist in a physical form that is stable, non-hygroscopic and easily formulated.